Self-assembled core-shell nanoparticles with embedded internal standards for SERS quantitative detection and identification of nicotine released from snus products.

Surface enhanced Raman spectroscopy (SERS) is a unique analytical technique with excellent performance in terms of sensitivity, non-destructive detection and resolution. However, due to the randomness and poor repeatability of hot spot distribution, SERS quantitative analysis is still challenging. Meanwhile, snus is a type of tobacco product that can release nicotine and other components in the mouth without burning, and the rapid detection technique based on SERS can reliably evaluate the amount of nicotine released from snus, which is of great significance for understanding its characteristics and regulating its components. Herein, the strategy was proposed to solve the feasibility of SERS quantitative detection based on self-assembled core-shell nanoparticles with embedded internal standards (EIS) due to EIS signal can effectively correct SERS signal fluctuations caused by different aggregation states and measurement conditions, thus allowing reliable quantitative SERS analysis of targets with different surface affinity. By means of process control, after the Au nanoparticles (Au NPs) were modified with 4-Mercaptobenzonitrile (4-MBN) as internal standard molecules, Ag shell with a certain thickness was grown on the surface of the AuNP@4-MBN, and then the Au@4-MBN@Ag NPs were used to regulate and control the assembly of liquid-liquid interface. The high-density nano-arrays assembled at the liquid-liquid interface ensure high reproducibility as SERS substrates, and which could be used for SERS detection of nicotine released from snus products. In addition, time-mapping research shows that this method can also be used to dynamically monitor the release of nicotine. Moreover, such destruction-free evaluation of the release of nicotine from snus products opens up new perspectives for further research about the impact of nicotinoids-related health programs.

The volatile release evaluation of nicotine from snus products under different storage conditions based on surface-enhanced Raman spectroscopy technology.

Surface enhanced Raman spectroscopy (SERS) is a highly sensitive analytical detection technique that provides unique chemical and structural information on target molecules. Snus is a type of tobacco product that can release nicotine and other components under certain humidity and temperature without burning, and the evaluation of its nicotine release under different storage conditions is very important for understanding its characteristics, regulating its components, and setting reasonable storage conditions. Herein, by means of an artificial climate box and suction extraction device, the volatile release evaluations of nicotine from snus products under different storage conditions were performed based on Fe3O4 microparticles coated with Au nanorods and Au nanoparticles (Fe3O4@AuNRsNPs) as SERS substrates combined with a capillary. The Fe3O4@AuNRsNPs assemblies can be fixed in the inner wall of the capillary with the aid of an external magnetic field, which improved the maneuverability of the SERS substrates. By comparing the intensities of the spectral peaks of the symmetrical breathing of the pyridine moiety of nicotine molecules with increasing temperature and humidity, which could significantly accelerate the volatile release of a small amount of nicotine, the nicotine release under different conditions could be evaluated. Based on this strategy, it was possible to obtain the storage or placement conditions of the product. The results of this study provide a reference to clarify the volatile release of nicotine under various storage conditions, which is helpful for better regulation of the levels of nicotine in snus. Moreover, such destruction-free evaluation of the volatile release of nicotine from snus products under different storage conditions opens up new perspectives for further research about the impact of nicotinoids on smokers' health and cessation programs.

Integrative analysis of sensory evaluation and non-targeted metabolomics to unravel tobacco leaf metabolites associated with sensory quality of heated tobacco.

Introduction: Heated tobacco (Nicotiana tabacum L.) products are heating tobacco plug at a temperature of 350°C and produce different emissions in aerosol and sensory perceptions of tobacco leaf compared with combustible tobacco. Previous study assessed different tobacco varieties in heated tobacco for sensory quality and analyzed the links between sensory scores of the final products and certain chemical classes in tobacco leaf. However, contribution of individual metabolites to sensory quality of heated tobacco remains largely open for investigation. Methods: In present study, five tobacco varieties were evaluated as heated tobacco for sensory quality by an expert panel and the volatile and non-volatile metabolites were analyzed by non-targeted metabolomics profiling. Results: The five tobacco varieties had distinct sensory qualities and can be classified into higher and lower sensory rating classes. Principle component analysis and hierarchical cluster analysis showed that leaf volatile and non-volatile metabolome annotated were grouped and clustered by sensory ratings of heated tobacco. Orthogonal projections to latent structures discriminant analysis followed by variable importance in projection and fold-change analysis revealed 13 volatiles and 345 non-volatiles able to discriminate the tobacco varieties with higher and lower sensory ratings. Some compounds such as ß-damascenone, scopoletin, chlorogenic acids, neochlorogenic acids, and flavonol glycosyl derivatives had strong contribution to the prediction of sensory quality of heated tobacco. Several lyso-phosphatidylcholine and lyso-phosphatidylethanolamine lipid species, and reducing and non-reducing sugar molecules were also positively related to sensory quality. Discussion: Taken together, these discriminating volatile and non-volatile metabolites support the role of leaf metabolites in affecting the sensory quality of heated tobacco and provide new information on the types of leaf metabolites that can be used to predict applicability of tobacco varieties for heated tobacco products.

Establishment of Routine Clinical Indicators-Based Nomograms for Predicting the Mortality in Patients With COVID-19.

This study aimed to establish and validate the nomograms to predict the mortality risk of patients with coronavirus disease 2019 (COVID-19) using routine clinical indicators. This retrospective study included a development cohort enrolled 2,119 hospitalized patients with COVID-19 and a validation cohort included 1,504 patients with COVID-19. The demographics, clinical manifestations, vital signs, and laboratory tests of the patients at admission and outcome of in-hospital death were recorded. The independent factors associated with death were identified by a forward stepwise multivariate logistic regression analysis and used to construct the two prognostic nomograms. The nomogram 1 was a full model to include nine factors identified in the multivariate logistic regression and nomogram 2 was built by selecting four factors from nine to perform as a reduced model. The nomogram 1 and nomogram 2 showed better performance in discrimination and calibration than the Multilobular infiltration, hypo-Lymphocytosis, Bacterial coinfection, Smoking history, hyper-Tension and Age (MuLBSTA) score in training. In validation, nomogram 1 performed better than nomogram 2 for calibration. We recommend the application of nomogram 1 in general hospitals which provide robust prognostic performance though more cumbersome; nomogram 2 in the out-patient, emergency department, and mobile cabin hospitals, which depend on less laboratory examinations to make the assessment more convenient. Both the nomograms can help the clinicians to identify the patients at risk of death with routine clinical indicators at admission, which may reduce the overall mortality of COVID-19.

Simultaneous extraction and surface enhanced Raman spectroscopy detection for the rapid and reliable identification of nicotine released from snus products.

Surface enhanced Raman spectroscopy (SERS) is a highly sensitive analytical detection technique that provides unique chemical and structural information on target molecules. Here, simultaneous extraction and SERS detection of nicotine for the rapid and reliable identification of nicotine released from snus products were performed based on a nano-Au assembly hierarchy structure in the capillary. Based on this strategy, the time evolution of the concentrations of nicotine released from the snus products was measured. Through comparison of the intensities of the spectral peaks of the symmetrical breathing of the pyridine moiety of nicotine molecules, with the prolongation of time, the concentration of nicotine released decreased significantly, which is helpful for establishing a method for the rapid evaluation of the processing and selection of excipients of snus products, and provides a new idea for further study of the production of snus pouches and related tobacco products. Moreover, based on data fitting, it can be calculated that the concentration of nicotine in the extraction presented an obvious quadratic relationship with time, and the release of most of the nicotine in the snus pouch, which is held through the gums and palate, was basically completed after ∼15 min. Such destruction-free simultaneous measurements of snus products are opening up new perspectives for further research about the impact of nicotinoids on smokers' health and cessation programs.

mGPDH Deficiency leads to melanoma metastasis via induced NRF2.

Oxidative stress critically influences carcinogenesis and the progression of melanoma, and aggressive malignant melanoma activity is due to its high metastatic ability. Some findings in several cancer cell lines have indicated that mGPDH, a component of the mitochondrial respiratory chain, also modulates oxidative stress. However, the role of mGPDH in melanoma remains elusive. Here, we report that the mGPDH protein level is decreased in human skin melanoma compared to normal skin and decreased in metastatic melanoma compared to primary melanoma. Our in vivo and in vitro experiments indicated that mGPDH depletion accelerated melanoma migration and invasion without affecting proliferation or apoptosis. Mechanistically, we found elevated NRF2 protein levels in human skin melanoma and mGPDH-knockout (ko) metastatic xenografts in the lungs of nude mice. Moreover, in A375 melanoma cells, the loss of mGPDH-induced NRF2 expression but did not affect NRF2 protein degradation. Additionally, melanoma metastasis induced by the loss of mGPDH was rescued by the further down-regulation of NRF2 in vivo and in vitro. Consistently, mGPDH overexpression (oe) depressed NRF2 expression and attenuated the malignant properties of melanoma cells. In conclusion, our findings suggest that mGPDH suppresses melanoma metastasis by inhibiting NRF2 and downstream oxidative signals, highlighting the therapeutic potential of mGPDH for melanoma treatment.

Overcoming drug-resistant lung cancer by paclitaxel-loaded hyaluronic acid-coated liposomes targeted to mitochondria.

As a major cause for the inefficiency of cancer chemotherapy, multidrug resistance (MDR) has become a major barrier to cancer treatment. Mitochondrion-orientated transportation of smart liposomes has been developed as a promising strategy to deliver anticancer drugs directly to tumor sites and actively target the mitochondria, so that drugs can interfere with mitochondrial function and facilitate cell apoptosis, overcoming MDR. Herein, we report a novel dual-functional paclitaxel (PTX) liposome system possessing both CD44-targeting and mitochondrial-targeting properties to enhance drug accumulation in mitochondria and trigger apoptosis of drug-resistant cancer cells. Mitochondria-targeting PTX-loaded liposomes were prepared by thin-film hydration and then coated with hyaluronic acid (HA) by electrostatic adsorption. We evaluated the characteristics of the PTX liposomes in vitro, and found that their particle size was about 100 nm and increased to ∼140 nm after modification by HA. The entrapment efficiency was larger than 85%, and stability data indicated that the liposomes were physically and chemically stable for at least one week at 4 °C. We further evaluated the intake, mitochondrial targeting, ATP levels, caspase-3 activity measurement, and antitumor actives of the liposomes. The results indicated that HA-coated liposomes with mitochondria targeting had significant inhibitory effects against A549 and A549/Taxol cells, showing them to be a promising means of improving therapeutic efficacy and overcoming MDR in cancer treatment.

Using hyaluronic acid-functionalized pH stimuli-responsive mesoporous silica nanoparticles for targeted delivery to CD44-overexpressing cancer cells.

In this study, novel hyaluronic acid-pH stimuli-responsive lipid membrane mesoporous silica nanoparticles (HA-PL-MSNs) were designed and assembled, with the chemotherapeutic agent doxorubicin (DOX) as the model drug. HA-PL-MSNs exhibited a well-defined mesostructure covered by lipid bilayer and particle size of ~150 nm. The drug loading capacity was up to ~18.2%. DOX release could be effectively retained by the lipid bilayer in pH 7.4 buffer and exhibited a pH-triggered burst release in the acidic condition. Confocal laser scanning microscopy and fluorescence-activated cell sorting showed that HA-PL-MSNs exhibited higher cellular uptake efficiency via CD44 receptor-mediated endocytosis compared with PL-MSNs in HeLa cells. In vitro cytotoxicity studies demonstrated that HA-PL-MSNs could effectively enhance the targeted delivery of DOX and restrain the growth of HeLa cells. This might provide a promising alternative for the development of a targeted anticancer drug delivery system.

The Prevalence of Thyroid Nodules and an Analysis of Related Lifestyle Factors in Beijing Communities.

Thyroid nodules (TNs) have annual increasing trends worldwide, and large-scale investigations on the prevalence of TNs in Beijing communities have not been conducted since the introduction of salt iodization in 1995. We performed a cross-sectional study to determine the prevalence of TNs, their epidemiological characteristics, and their correlation with lifestyle factors. A total of 6324 permanent residents aged 18 years or older (mean age, 52.15 ± 11.58 years) from seven representative communities in Beijing were included in the analyses. Once informed consent was obtained, the subjects were asked to complete questionnaires, a physical examination, and thyroid ultrasound. A total of 3100 cases had TNs. The overall prevalence rate was 49.0%, and the age-standardized prevalence was 40.1%, which increased significantly as age increased (p < 0.001). The prevalence was significantly higher in females compared to males (p < 0.001), and it was significantly higher among female current smokers and former smokers compared to non-smokers (p = 0.007). There was no correlation between alcohol consumption and TNs, and there were no significant differences in the prevalence among different groups of taste preference. The prevalence decreased with an increased frequency of seafood intake (p = 0.015) and with higher literacy levels (p < 0.001). The Cochran-Armitage trend test showed that the prevalence significantly increased with decreased physical labor and exercise intensity (p < 0.001, p = 0.009). Logistic regression analysis showed that age (Odds ratio (OR) = 1.039 (1.034-1.044), p < 0.001), the female sex (OR = 1.789 (1.527-2.097)), Body mass index (BMI) (OR = 1.019 (1.005-1.034)), and current smoking habits (OR = 1.246 (1.046-1.483)) were independent risk factors for TNs. Our findings indicate that there is a high prevalence of TNs in Beijing, with a higher prevalence in females than in males. Moreover, the prevalence increases as age increases. Smoking and BMI are independent risk factors for TNs. Therefore, intervention against smoking and weight loss might help reduce the risk of TN occurrence.

New validated LC-MS/MS method for the determination of three alkylated adenines in human urine and its application to the monitoring of alkylating agents in cigarette smoke.

A highly specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of urinary N(3)-methyladenine (N(3)-MeA), N(3)-ethyladenine (N(3)-EtA), and N(3)-(2-hydroxyethyl)adenine (N(3)-HOEtA). Chromatographic separation was achieved on a hydrophilic interaction liquid chromatography column, with a mobile phase gradient prepared from aqueous 10 mM ammonium formate-acetonitrile (5:95 v/v, pH 4.0). Quantification of the analytes was done by multiple reaction monitoring using a triple-quadrupole mass spectrometer in positive-ionization mode. The limits of quantification were 0.13, 0.02, and 0.03 ng/mL for N(3)-MeA, N(3)-EtA, and N(3)-HOEtA, respectively. Intraday and interday variations (relative standard deviations) ranged from 0.6 to 1.3 % and from 3.7 to 7.5 %. The recovery ranges of N(3)-MeA, N(3)-EtA, and N(3)-HOEtA in urine were 80.1-97.3 %, 83.3-90.0 %, and 100.0-110.0 %, respectively. The proposed method was successfully applied to urine samples from 251 volunteers including 193 regular smokers and 58 nonsmokers. The results showed that the levels of urinary N(3)-MeA, N(3)-EtA, and N(3)-HOEtA in smokers were significantly higher than those in nonsmokers. Furthermore, the level of urinary N(3)-MeA in smokers was found to be positively correlated with the level of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (r = 0.48, P < 0.001, N = 192). This method is appropriate for routine analysis and accurate quantification of N(3)-MeA, N(3)-EtA, and N(3)-HOEtA. It is also a useful tool for the surveillance of alkylating agent exposure.

Simultaneous determination of chromium, cadmium, and lead and evaluation of the correlation between chromium and cotinine in Chinese smokers.

Heavy metals in tobacco caused wide public concern. To study the impact of heavy metals in smokers, 193 smokers and 58 nonsmokers were surveyed, and their urinary levels of chromium (UCr), lead (UPb), and cadmium (UCd) were assayed. In this study, UCr, UPb, and UCd in smokers (33.41 ± 14.99, 3.21 ± 1.34, 0.38 ± 0.64 µg/24 h, respectively) and nonsmokers (27.45 ± 10.49, 3.02 ± 0.88, 0.20 ± 0.16 µg/24 h, respectively) were determined by inductively coupled plasma mass spectrometry. The results showed that the content of UCr, UPb, and UCd in smokers were higher than in nonsmokers. Further analyses of correlations between the levels of urinary chromium and cotinine revealed positive relationship (correlation coefficient r = 0.51).

Development of a method for the determination of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in urine of nonsmokers and smokers using liquid chromatography/tandem mass spectrometry.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is an efficient biomarker of tobacco-specific carcinogen 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). The ability to monitor biomarker concentrations is very important in understanding potential cancer risk. An analytical method using molecularly imprinted polymer (MIP) column coupled with liquid chromatography/tandem mass spectrometry (LC-MS/MS) for the determination of total NNAL in human urine was developed and validated. The combination of MIP column extraction and LC-MS/MS can provide a high sensitive and relatively simple analytical method. The limit of detection (LOD) was 0.30 pg/ml and analysis time was 6min. The method has been applied to urine samples of 36 nonsmokers and 207 smokers. NNAL was found to be significantly higher in the urine of smokers compared with nonsmokers. Compared with smokers with blended cigarettes, Chinese virginia cigarettes smokers had low urinary NNAL levels. There was a direct association between the 24-h mouth-level exposure of carcinogen NNK from cigarette smoking and the concentration of NNAL in the urine of smokers. However, there was not a positive correlation between urinary total NNAL levels in 24 h and tar. Total urinary NNAL is a valuable biomarker for monitoring exposure to carcinogenic NNK in smokers and in nonsmokers. A prediction model of cigarette smoke NNK and urinary average NNAL levels in 24 h was established (y=2.8987x-245.38, r²=0.9952, n=204).